1. Field of the Invention
The present invention relates to a digital video recorder such as a digital versatile disc (DVD) recorder, a hard disc drive (HDD) recorder, a digital video cassette recorder (VCR), and the like that can be connected to a digital video (DV) camcorder via an IEEE 1394 serial bus so as to record DV streams sent from the DV camcorder.
2. Description of the Related Art
It is known to connect a digital video recorder such as a DVD recorder, a HDD recorder, or the like to a DV camcorder via an IEEE 1394 serial bus for, e.g., copying data captured on a DV tape in the DV camcorder to the DVD recorder or the HDD recorder. Where a DV camcorder and a digital video recorder are connected to each other via an IEEE 1394 serial bus, the digital video recorder serves as a controller, which allows a user to copy data from the DV camcorder to the digital video recorder only by entering a command into the digital video recorder. This is hereinafter called “program dubbing”.
More particularly, when a user enters a command for program dubbing into the digital video recorder by operating input means such as a remote control, the digital video recorder first issues a command to rewind a DV tape to the DV camcorder so that the DV tape in the DV camcorder is rewound to the beginning. When the digital video recorder recognizes that the DV tape has been rewound to the beginning based on a time code acquired from the DV camcorder, the digital video recorder then issues a play command to the DV camcorder so as to instruct the DV camcorder to reproduce data from the DV tape. With the reproduction, the DV camcorder sends, to the digital video recorder, DV streams, which are recorded on a digital recording medium such as a DVD, a hard disk, or the like in the digital video recorder.
Some kinds of program dubbings allow setting of a recording time for copying data from a DV tape to a digital video recorder (for example, allows 30 minutes of video to be copied from the beginning of the DV tape).
Further, in a conventional system, a personal computer is connected to a plurality of DV camcorders so that the personal computer can be used to control editing of video and audio data recorded on the DV camcorders (see, for example, Japanese laid-open patent publication 2002-184057). When locating the beginning of data on a DV tape, the system changes the rewind speed stepwise based on a difference between the target position on the DV tape and the current position on the DV tape.
Conventional digital video recorders determine that rewind of a DV tape has been completed, if a time code acquired from a DV camcorder is either “00:00:00:00” or “-:-:-:-”. Otherwise, the digital video recorders determine that the rewind has not been completed yet.
When determining that the rewind of the DV tape was not properly completed, the digital video recorders stop the program dubbing sequence without issuing a play command to the DV camcorder. The reason for stopping the operation requested by a user is as follows. Even though the program dubbing is set, a user may possibly press a button to stop rewinding a DV tape in the DV camcorder by mistake during the actual operation. Usually in such a case, the DV tape is not completely rewound to the beginning. Therefore, if the program dubbing is continued (i.e., if a play command is issued to the DV camcorder) even in such a case, the copy may be incomplete with video/audio data near the beginning of the DV tape missing or not recorded.
In order to copy video/audio data recorded on a DV tape to a digital video recorder properly from the beginning, the digital video recorder needs to determine whether or not a time code acquired from a DV camcorder is a predetermined value (e.g. “00:00:00:00”). However, the following trouble may occur in the conventional system. There is a case where the digital video recorder acquires only an improper time code such as “00:00:00:04” from a DV camcorder although a DV tape has been properly rewound to the beginning. In this case, the digital video recorder cannot recognize the proper completion of the rewind of the DV tape. Therefore, the digital video recorder may stop the sequential process such as program dubbing.
Whether the above described trouble occurs or not depends on the model of a DV camcorder connected to the digital video recorder or on the operating condition. In view of that, one possible cause of the trouble is that the timing of acquisition of a time code from a DV camcorder by the digital video recorder does not coincide with the timing of operation on the DV camcorder. More particularly, the trouble may occur because the digital video recorder acquires a time code before a DV tape is actually rewound to the beginning, and the acquired time code is not updated but kept as a final time code in a memory in the digital video recorder.